More than any other nationality surveyed, 64 percent of U.S. travelers said they have urinated in the ocean or pool.

Another 69 percent admitted to snagging extra hotel toiletries for their own use back at home.

The percentages were significantly lower for Canadian, German, British and Chinese respondents.

"When we leave our bubble, when we actually go on vacation, when we're surrounded by people who don't know who we are, it just becomes a heck of a lot easier to do things that we would otherwise frown upon and find unacceptable," said Gabe Saglie, senior editor for Travelzoo.

Saglie said the findings may also point to the fact that Americans get fewer vacation days than workers in many other countries, so when the time comes for a break, they "let loose."

Americans also topped the percentages for those who have skipped out on a bill (13 percent) or faked a sickness to extend vacation (24 percent).